Machine-switching telephone-exchange system.



A. B. SPERRY.

MACHINE SWITCHING TELEPHONE EXC HANGE SYSTEM.

APPLICATION FILED JULY 21.1915.

1,246,176. Patented Nov. 13, 1917.

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APPLICATION FILED JULY 27.1915. Patented NOV. 13,1917

L 3 SHEETSSHEET 2- I g a A rf/wr b? Spe'rry. 02W by A. B. SPERRY.MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED, JULY 27.1915- Patented Nov. 13, 1917.

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UNI f 7 ARTHUR BRUCE sjrnnntr, on NEW Yo i; 1v. Y., Assicrnon, BY MESNEASSIGNMENTS-,7 TO' WESTERN ELECTRIC COMPANY, INCORPORATED,e'conrona'rron or nnwgvonx.

, M cmmswmme i'ntnrno vn-nxcnanen sirsrnn;

a To all whom it may concern:

Be it known that I,- ARTHUR Button 7 SPERRY, a citizen of the UnitedStates, re- V .siding at New York,"in the county Of'NGW "5 York andStateof New York,ha've invented certain new 1 and useful Improvements inQgMa'chine -SwitchingfTelephone- Exchange Systems, of which thefollowing is afull,

'clearg concise, and exact description, V .10 This invention relates to{telephone ex} change "systems employing} machine :switching, andparticularlyto that; type of system employing automatic finder; switchesfor extending'calling' lines to fc'onnecting'circuits, V wherein thefinders are apportioned to "callmg lines by an extendedstarter wire andall ,of the apparatus individual to one subscribers line and" a. portionof theapparatus individual'to another in the-same group, and apparatuscommon to the entire group I,

35 of'lines,,'that individual to the lines-"being shown toithe left,-and that common to the group to the'right, of the dotted line; Fig; 2 r

Goodrum upon which this system isan' improvement, only as much of thecircuits and apparatus as; is essential to "an understand- 50 ing ofthis improvement will be described herein.

i T he isubscribers 'lines' 111,112 termi'nate 1 in multiple'terminals224,225 of automatic finder switches, the number-depending on "55 thetr'afic. A multiple test-terminal 226' is Application filed Iuly 27,1915se'ri i nmaiss; a

Referring"tothe' draWings,-Figu'reil shows" on the shaft carryingitheesets of. brushes 221, '222,- 223. .i This brush 2, during the :rotary'movemento'f the 'brush.i'shaft,; wipes overigroup terminals, 1', 2,,etc.,aonthe aux-1. :iliary switch 7 to; which iti belongs, 1 and whenthereon is reached, this rotary movement" is stopped, the desired setlofbrushes-at this 7 Specification of iettersfatent, Nov,

ofa call in any of i the linesi to whichflit ibepears, andsimultaneously closes the-"circuit associated'with eachlineu' Each lineis-gprof i vided-With line and cut-ofi' relays:o.., :u, and I each groupof lines with a startingzrelay 05. 1 This relayis energizediuponthesinitiation .ff .i '4;

60 :-10ngs,.its circuit beingcompleted attire :armature and frontcontact-oftheline relay -.'v ofsuch linelif The energization oflrelay gogrounds a'terminal 1 (Fig. :2), multipled' to auxiliary or group.iswitchesl S 1 on; the find'ers in which :such-group-of alines a'p of'the primary stepping magnet ;205 of'the 1 finder. serving this group, ifsuch finder be idle, If :busy, the arm if (Fig -2) ;ofthe{ side switchof this finder-willgbesin'gposition g s 3ythusextending theistarterwirek tocon-i ductor 7; which leads; torlthe primaryxflstep- 5 Each finderbrush shaft (not shown carries a set 'ofibru'shes 221,222,223 for eachgroup ping magnet 205 ,off the next-idle finder. 7

of: lines, and may berrotated by the primary stepping magnet 205 thereofto pos it-ionta'n'y set in operative relationltopthemapett r, y minalsi'it serves; This set will "then, upon 80, the elevation of the brushshaft .due'tothe Y operation? of the. secondary ,steppinglma-gnet-207 ofsuch-findenywi'pe oversuch gro p iii-search of the calling-dine. lnlorder to position the proper/set of brushes inopera tive: relation tothe 1 calling group, the ;aux iliary switch S- 'referred-;to is providedfor each. finder having a brush zUmounted on i I the grounded terminal:of the callinggroup timebeing properlypositioned; below" the terminalsof the calling: line group. The secondary magnet 2.07, is'thenfoperatedgto :7

- Assuming the finder of Fig, 2, which is elevate-the brush shaft;

adapted normally to serve groupG' (Fig.

-3)-,..to be =idle,,the arm .2; (Fig.2) ,of the I groupfiswitch ;S, sofisuch finder rests'on a home contactawFof'gsucih auxiliary gswitch.:71.05 V, Itis necessary to rotate the brush shaftpnestep,to'properlyfpositionthesetof brushes 1 3 serving line group 'GIto'WiPQOVr the-mule tiples 224, 225, 226 thereof in search of the callingline; therein, upon thesubsequentjg e at of the secondary steppingmagnet 207. This magnet 207 elevates the brushes and the arrival of thetest brush 223 upon the calling line test terminal .26 energizes thecutoff relay 20 thereof. This relay in operating, opens the circuit ofthe group relay c, which in turn opens the stepping circuit of magnet207 to stop the finder on' the calling line terminals. The calling lineis now extended to a first selector and the stepping relay 23% thereofmay be operated by the sender a to set such selector in the wellknownmanner.

The invention will be more readily understood by tracing a call. hen thesubscriber at substation A (Fig. 1) removes his receiver, a circuit isclosed for line relay '0, this circuit leading over the line conductors111, 112 and through the telephone set at substation A. This relaythereuponcloses a circuit for relay 0 to start a finder, this circuitleading from the free pole of battery, through the left winding of relay1), left armature and back contact of cut-off relay u conductor 121,contacts 117, 118 of the line relay o, conductor cl, relay 0 to ground.

Bela 0 at its right armature and uaaer front contact thereupon closes acircuit for the primary magnet 205 (Fig. 2), to rotate the brush shaftto position the set of brushes on the brush rod individual to a callinggroup in operative relation to the terminals of such group, assumingthat the line finder normally associated with the starter wire it beidle. Under such assumption the arm .2 of the finder brush rod is incontact with home segment at. This circuit is as follows: free pole ofbattery (Fig. 2),magnet 205,conductors 212, 275, arm 210, conductors209, 208, conductor 266, armature and back contact of magnet 205,conductor 201, armature and back contact of magnet 203, conductors 202,7), arm 2', conductor is, slow relay 7), conductor it, right armatureand upper front contact of relay 0 to ground. The magnet 205 rotates theshaft one step and carries arm 2 of group switch S into contact withgroup segment 1, grounded by the energization of relay 0', when acircuit is closed for magnet 217 which is the side switch escapementmagnet, and magnet 205 inseries as follows: free pole of battery, magnet205, conductor 212, magnet 217, conductor 218, arm 216 and its firstcontact, conductor w, arm 2, contact 1 of switch S, conductor 9,armature and front contact-s of relay 0 to ground. The circuit forstepping magnet 205 previously traced is at this time open at thearmature and back contact of said magnet and therefore, is not in shuntof the circuit just traced for magnet- 217. The 'escapement magnet 217energizes and the magnet 205 remains energized. Magnet 217 in attractingits armature allows the side switch to move to position 2, in whichposition the circuit for the magnets 217, 205 is maintained, thiscircuit being as follows: (Fig. 2) free pole of battery, magnet 205,conductor 212, magnet 217, conductor 218, arm 216 now in position 2,conductor 287, conductors 202, p, arm'i, conductor relay Z), conductor7b, ri ht armature and upper front contact of relay 0 to ground. Inparallel with the circuit just traced, the following circuit is closedfor the secondary stepping magnet 207: free pole of battery, magnet 207,conductor 219, arm 210 and its second contact, conductors 209, 208,armature and back contact of magnet 207, conductor 266, right armatureand front contact of escapement magnet 21.7, conductor 267, conductor 201, right armature and back contact of release magnet 203, conductor 202,conductor p, arm a" and its second contact, conductor is, relay 7),conductor it, right armature and upper front contact of relay 0 toground. The magnet 207 by interrupting its own circuit elevates theselectedset of brushes 221, 222, 223. )Vhen the brushes arrive upon theterminals 224, 225, 226 of the line of the subscriber initiating thecall, the cut-off relay a of such line is energized over the followingcircuit: free pole of battery (Fig. 1), relay in, conductor 11 1,terminal 226, brush 223, conductor 113, contacts 228, 270 of escapementmagnet 217, conductor 271, resistance 272, conductor 3?, arm 2" and itssecond contact, COnduCtOr 7c, relay 5, conductor h,

to ground at the right armature and upper front cont-act of relay 0.Cutoff relay to at is also opened at the right armature and upper frontcontact of relay 0. The side switch is constructed to move frompositions 2 to 3, upon the deenergization of the escapement magnet 217.The closure of contacts 228, 229 by magnet 217 in (lo-energizing, placesground on the multiple test terminals of this line over conductor 230and left armature and back contact of magnet 203, whereby connectioncannot be made to it by a connector. In this position arms 232, 233 ofthe side switch connect the line conductors 111, 112 through to thestepping relay 23 1 of the selector. The relay 234; is nowintermittently operated by the calling subscriber in actuating hissender s in the well-known manner.

Referring now to Fig. 3, this figure in conjunction with Figs. 1 and 2shows the circuit arrangement of this invention which provides forallowing a second call to pass out of a group while the line findernormally assigned thereto is operating. Ordinarily, a calling 5subscriberof a group. would be 'blockedas longas the finder adaptednormally. to serve such group is operating, and could not start an idlefinder until its associated finder hadv fully operated and'ha'd extendedthe starter 'Wire to the next finder,

since the starting conductor login'clu'desthe side; switch armvY,Whichadvances during the operation of the finder i in connecting with acalling line, and -such' starting wire until-the-side switch arm z"reaches its third contact. The circuit'arrangeinent about to bedescribed operates toextend the starting ground to theenext. idle finderimmediately, -ifthe associated finder is operating tocon- 'nect Withfi/calling line in another' group. This will i be more -readily apparentfrom a I consideration of Figs. 1,'2 and '3.

Ass mingthat a subscriber infthe'second I ,group G (Fig. 3) initiates acall; and'that tion of a call, closes 'the following circuit to'startthe 'nextidle line finder, which We Will assume to befthe-findernormally asjsignedto' group ;G:' ground, armature andthe"finder?normally nssigned thereto be in.

use. The side -svvitch'rarm of such" finder -ivould-in such case-beinieng'agement with its third contact (Fig. 3).

, Therefore the energization' of the relay 0 upon the initiaupper front-,contact of relay c conductor involving such finder restore theirreceivers.

h ,'-.re1ay b ,conductor k arm-'71" and its third contact, starting Iconductor f left armature-and-back contact of relay 7 of line group G,conductor relay a, to free vpole of battery, Belay'fb fby opening itsback contact opens-the connection betweenthe release conductors n 0toprevent the finder normally assigned to group G- 'from' releasing Whenthe parties to the connection J Sucli finder in restoring would restorethe.

conductors p, 202, right armature and back i side switcharm z' 'andwouldthus break the starting circuit just traced; Relay a at its rightarmature and lower front contact locks itself togstarting conductor f3,and at its upperfront contact connects the grounded conductorf to'conductor c which leads to the primary stepping magnet 2050f the finderof group G (Fig.2). This circuit I may be continued by reference toFigs. 1 and 2f Continuing therefore from conductorfh (Fig. 1), relay.5', conductor side; sWitch' -arm i. and its 5 front contact,

contact of release magnet 203, conductor 204,

ri'ghtarmature and-back contact 'ofprimary magnet 205,?coiidu'ctor 266,le ft armature and fb'ac'k contact of magnet 207,.conductors i 208, 209,arm 210'; audits firstv contact, con

ductors 275, 212, primary stepping 'magnet 205, to battery. The magnet205 makes and breaks its own circuit, rotating the brush rod until*th'ean; gan -agathe-multiple 3 contact 2 of group switch S. individual=tocalling line groupG thereon. fA. groundlisl, 1 I placedonthis contactatthe right armature an'd'front contacts of relay c -byway' of conductor 9 (Fig. 3). Whenthe arm e ene "gages this'segn'ient', acircuit'fo'rlthe escape- 1 mentmagnet 217V and primarymagnet 205 isclosed, this circuit bjeing'independentlof the armature'and back contactof saidyprilnary magnet, whereby-the sameusmaim tainedenergizediasbefore and the motion -of the shaft st'opped. i' This circuit may betraced asfollows'z free pole of battery 7 cuit is maintained overthefollowing path:

free pole of battery, magnet 205, conductor 212, magnet 217,0'onductor218, arm 2 16, conductors 287, 202, 1)" (Fig.3), arm-i and; its "secondcontact, conductor} is, relay 6,

conductor; it, arni'ature'i and supper gfront contact of relay a,conductor figar'm'ii and with the circuit just traced, to move thebrushes 221, 222', 223 so positioned overthe terminalsof the-callinglinegroup G 'zf-ree pole of battery, magnet 207 "(Fig. 2),.jconductor 219,arm 210 and second contact, con-- 1 its third contact, conductor. 70?,relay (9%,; conductor-72 ,arn1ature and .u'pper' front contact of relaya ,-'to ground; In position 2,the following circuit is closed for'theifsec ondary stepping magnet/207, in parallel,

du'ctors 209, 208,-ar niature and 'back contact of magnet 207,conductor'266,"rightarrna- 'ture and front contact of. magnet217, 0onductors 267', 204-, right armature and back contact of magnet 203,-con'du'ctors 202,: ;,1'10

arm i and its secondcontact' (Fig; con-n ductor it-Qrelay' b,conductor72/, right arma- 'ture "and upper front contact of relay a, conductor 7,arm 2' audits third contact,

conductor 70 relayb yconductor h right armature and upper front contactof relay 0 to ground. The magnet 207 at-its armature and back contactinterrupts? its circuit,

thusstepping the said brushes221, 222, 223 over the terlninalslof the.calling line group. The cut-ofif'relaya -ofthe calling'linecorrespending to relay fLb' of'Fig l. is operated Whenthe'br'ush 223'rea'chesthe test terminal 226 ofsuch'line. -This'relay-at': its leftarmature and back 'contact deenergizes the group relay 0 which, byretracting its right armature,opens the circuit just traced for thestepping magnet 207, whereupon finder brushes 221, 222, 223come to restupon the cal-ling line terminals. The escapement respondi to magnet 21?is deenergized by the deenergization'of the relay 0 and allows the sideswitch to more to position 3, whereupon the calling line is extendedthrough to stepping relay 234- of the first selector as before.

Assuming now that While these operations are taking place a subscriberin group G initiates a call, that is to say, that this call is initiatedbefore the s de switch arm 2' of the finder normally serving group G hasreached position 3. The energization of the relay a" by the incomingcall from group G just traced, connected conductors r and 8 together atthe left armature and front contact of said relay. The initiation of thecall in group G energizes the relay described. This relay at its leftarmatu. e closes the following circuit for a relay at the next idle linefinder cors, a of group G. Gnly three line groups are shown forsimplicity, the first. second and tenth. Assume the finder of the tenthgroup G to be idle. The circuit for its relay (4 may then be traced asfollows; ground, left armature of relay 0, conductors a, r. 7", leftarmature and back contact of relay 0 conductor relay (4 to free pole ofbattery. Relay (4 by its right armature and lower front contact, locksitself directly to grounded conductor 7, and at its upper contactextends said conductor 7' to conductor h relay 6 conductor 0 arm 2 andits first contact, conductor 72 to the primary magnet of the findernormally serving group G. This circuitv may be continued by referring toFig. 2, and as suming the finder shown thereon to be that normallyassigned to group G, conductors p, 202, armature and back contact ofrelease magnet 203, conductor 20%, armature and back contact of primarymagnet 205, conductor 266, armature and back contact of secondarystepping magnet 20?, conductors 208, 209, arm 210, conductors 275, 212,primary magnet 205, to free pole. of battery. Magnet 205 makes andbreaks its own circuit thus stepping around the arm 2 of the findernormally serving line group G When the arm 2 reaches mu tiple contact 1upon which ground was placed by the attraction of the right-handarmature of relay 0 (Fig. 3), the following circuit is closed: free poleof battery, magnet 205 of the finder of group G, conductor 212,escapement magnet 217, conductor 218, arm 216, conductor 20 arm 2contact 1 of auxiliary switch F5 conductor ([1, to ground at thearmature and front contacts of relay 0 (Fig. 8). It will be noted thatthis circuit does not lead through the armature and back contact ofprimary magnet 205, and therefore this magnet is maintained energized inseries With the escapement magnet 217. As before, the escapement magnetin energizing moves the side switch into position 2, in which positionit is maintained energized over the following circuit, still assum'ngthe finder shown in Fig. 2 to be the finder normally serving line groupG free pole of battery, magnet 205, conductor 212, escapement magnet217, conductor 218, arm 216, conductors 287, 202, 2?, arm 2' and itssecond contact (Fig. 3), conductor relay 6 conouctor it, right armatureand upper front contact of relay a conductors f, 1*, left armature andfront contact of relay (1,, conductor a, to ground at the left armatureand front contact of relay 0. In parallel with this circuit arefollowing circuit is closed for the secondary stepping magnet 20? of tle line finder in question: free pole of battery, magnet 207 (Fig. 2),conductor 219, arm 210 and itssecond conta t, conductors 209, 208,conductor 266, right arm ature and front contact of magnet 217,conductors 267, 20%, rig it a mature and back contact of release magnet203, conductor 202, conductor 39, side-switch arm 2' (Fig. 3) and itssecond contact, conductor :2 relay 2 conductor 71 right armature andupper front contact of relay a conductors left armature and frontcontact of relay a conductor a, left armature and front contact of relay0, to ground. The magnet 2th makes and breaks its own circuit thusstepping the select d set of brushes over the multiples of the callinggroup G in the line finder of group G. i l hen the test brush 223 ofsuch find r reaches the test terminal 226 of the callin line, the relayu isoperated ove the fol lowing circuit: (Fig. 1) free pole of battery,relay a, conductorll-ft, terminal 2 6, brush 223 of the finder,conductor 13, contacts 228, 270, conductor 271, resistance 272,conductor 7?, arm 1' (Fig. 3), conducto 70 relay b conductor 72,armature and upper front contact of relay {II/10, conductor 7",conductor 1", left armature and front contact of relay a, conductor 8,left armature and front contact of relay 0, to ground. The relay u atits left armature and back contact opens the circuit of relay 0' which,in retracting its left armature, removes ground from conductor f" thusstopping the finder upon the calling line terminal. The escapement-magnet 21? of the line finder is also deenergized by the removal. ofthis ground, and in decnergizing allfifi's the side switch of suchfinder to advance to its third position. in which the calling line isextended through to the first selector and the relay 23% thereat isenergized.

The removal of ground from starting conductor 7 by the deenergization ofrelay 0 deenergizes relays a and 22 The relay 6 in closing its rightback contact closes the break in the circuit of release conductors 0 aWhen the parties hang up their receivers the release magnet of theconnector is energized in the well-known manner and a ground is placedon conductor 277 leading therefrom. The placing ofthis ground uponconductor 277 closes the circuit of release magnet 203 of the finder asfollows free pole of battery, magnet 203, conductor 279, 0&- normalcontact 280, conductor 0, right armature and back contact of relay 7;,conductors n, 281, arm 284 of the selector side switch and its thirdcontact, conductor 282, brush 283, terminal 284, to grounded conductor277. hen the finder completely restores, therelease magnet isdeenergized by'the opening of off normal contact280.

The release magnet 203 in attracting its armature restores the sideswitch in the wella known manner. Therelease magnet 278 of the selectoris energized in parallel with release magnet 203 of the finder and inattractin its armature also restores the selector side switch. What isclaimed is:

. 1; In amachineswitching telephone system,-.in' combination with groupsof subscrlbers hnes, automatic finder switches to which said lines aremultipled, each of said switches being normally allotted to a group oflines, an extended starter circuit, and means operated over. saidstarter circuit when a line calls in one of said groups while sideswitches adapted to control said finders, a

a relay (0") v for each group of lines controlled by any line therein toclose the driving circuit of the associated finder, said circuitincluding an arm of said side switch I and its first contact, anextended starter wire adapted to be associated with a group relay (0)by'the closure of said side-switch arm' with its last contact when theassociated finder is taken for use, of a path at each finder in shunt ofthe side-switch arm therea of, and a relay (at) for each group adaptedto be operated by'a group relay (0) of another calling group over said,extended starter wire and controlling one break in said path, thecorresponding group relay (0) controllinganother break therein.

3. In a machine switching "telephone ex-. change system, the combinationwith sub-'; sc'ribers lines, finders to which said lines are multipledin groups, each group of lines having a finder normally adapted toservethe 4 same, drivmg circuits for sa1d finders, an; 65 7 extended starterwire for associating idle finders with calling lines,,a relay (0) foreach group of lines controlled by anyline therein to close the drivingcircuit of the associated finders, a contact arm included in each ofsaid driving circuits having normal and'oif-normal contacts, and means Ifor transferring said arm to an off-normal w contact to associate'thegroup relay thereof by said extended starter wire with the next idlefinder when the associated finder has connected with a calling line ofits group, of I a branch from said extended starter wire to each grouprelay independent of the correspon the corresponding branch circuit andadapt mg therein. a

In witness whereof, I

' ARTHUR BRUCE SPERRY.

floples of this patent may be obtained for five cents each, byaddressing the Commissioner of Patents,

7 [,Washingtomhfl.

ing contact, arm, and a relay ((1').

' for each group adapted to close one break in hereunto subscribe myname this 23rd day of July A, D. 1915. V

